The invention pertains generally to scales and weighing apparatus and more particularly to a system for providing a digital indication of the load on a scale.
Heretofore, there have been attempts to provide a digital indication of the load on a scale utilizing an absolute position encoder connected to the pinion or shaft of a mechanical weight indicator on the scale. The encoder produces a unique binary output signal for each incremental position of the shaft through up to 360.degree. of shaft rotation, and the binary signals so produced are decoded by electronic circuitry and processed for display or other desired use.
While an absolute position encoder is capable of providing all of the information required for determining the weight of the load, such devices are costly and complex, and they must be aligned very accurately to provide accurate results. Moreover, they are binary encoded devices which must simultaneously present a number of parallel data bits for each increment of displacement. The number of bits required is determined by the resolution of the scale and the accuracey of display desired. For example, in order to detect one ounce increments on a scale having a 75 pound capacity, eleven bits are required for each increment. The circuitry required for processing this number of bits is complex and relatively expensive.